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全文: "NOVA2001"
3件中 1-3の結果を表示しています
  • Hui-Li WANG, Jian-Zhong LI, Ji-Ye HU
    Analytical Sciences
    2006年 22 巻 12 号 1589-1592
    発行日: 2006年
    公開日: 2006/12/12
    ジャーナル フリー
    Solid-phase extraction (SPE) procedure for cleanup followed by HPLC-UV method has been investigated for the determination of pyraflufen-ethyl residues in soil. The pesticide is extracted from the sample with acetone-water (80:20, v/v) and the extract is loaded onto an octadecyl (C18) column. The pesticide is eluted with acetonitrile and determined by HPLC with a UV detector. Using an acetone-water extraction followed by a C18 cleanup, this method is characterized by recovery >90.1%, precision <5.8% RSD and sensitivity of 0.01 mg/kg. The proposed method has been successfully employed for the determination of the degradation dynamics of pyraflufen-ethyl in four agricultural soil samples under laboratory conditions.
  • Maria C. H. da SILVA, Luis H. M. da SILVA, Fernanda J. PAGGIOLI
    Analytical Sciences
    2005年 21 巻 8 号 933-937
    発行日: 2005年
    公開日: 2005/11/18
    ジャーナル フリー
    This work proposes a new method for Co(II) determination based on the use of the triblock copolymer as micellar medium instead of chloroform. The proposed strategy is environmental friendly because the copolymer is biodegradable and nontoxic. The method is based on the formation of a cobalt-1-nitroso-2-naphthol complex, in the micellar triblock copolymer compound solution constituted by polyethylene oxide (PEO) and polypropylene oxide (PPO). Experimental conditions such as pH, the molecular weight and the PEO/PPO ratio of triblock copolymer were optimized. Results obtained for cobalt determination in vitamins with this novel method showed excellent agreement with those obtained using atomic absorption spectrometry. The relative standard deviation for a solution containing 0.125 mg L-1 Co was 1.0% (n = 5); the relative error varied from 2.8 to 4.4%; the detection limit was 13.3 µg L-1 and the quantification limit was 44.3 µg L-1.
  • Sanford H. LEUBA, Jordanka ZLATANOVA
    Archives of Histology and Cytology
    2002年 65 巻 5 号 391-403
    発行日: 2002年
    公開日: 2005/10/14
    ジャーナル フリー
    With the advent of single-molecule techniques, macromolecular science has reached new horizons. Nowadays, we can observe, touch, stretch and twist biological macromolecules or their complexes, one-at-a time, in attempts to better understand their mechanical properties and to gain insights into their behavior in the living cell. Chromatin structure and function has been the focus of our research interests for many years. In the past decade, we have added some of the newly emerged single-molecule approaches to the more traditional biochemical and biophysical methods that we have been using throughout the years. This paper briefly summaries our studies on individual chromatin fibers using the atomic force microscope (AFM), optical tweezers, and magnetic tweezers. We believe that our results so far have contributed significantly to our understanding of chromatin, but we also hope that this is only the beginning, and that more exciting times lie ahead.
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